The paper deals with the calibration methods for machines with parallel kinematics. The procedures are based on Newton method for numerical solution of overconstrained system of nonlinear equations. The methods are applied on redundantly actuated machine with planar kinematics named ‘Sliding Star‘. The redundant measurements of relative motions in joints allow on-line calibration in real time of machine tool operation. This could significantly improve the thermal inaccuracy of machine tools with parallel mechanisms. and Obsahuje seznam literatury